1. Field of the Invention
The present invention relates to a photographing apparatus such as a digital camera and, more particularly, to a photographing apparatus that is radio-communicable with other photographing apparatuses.
2. Description of the Related Art
Digital cameras have become widely used in recent years, and a method of using a digital camera has become diversified. For example, some digital cameras are provided with a radio LAN function, which enables radio communication between digital cameras to exchange data of images taken by the digital cameras of each other. Japanese Laid-Open Patent Application No. 2007-142681 suggests a technique to send an IP address or a MAC address to a remote apparatus. Disclosed in this patent document is a communication method in which a digital camera stores an image of an encoded IP address or MAC address of the digital camera and another digital camera takes an image of the displayed encoded IP address or MAC address on a monitor and decodes the thus-taken image in order to enable the other digital camera to communicate with the digital camera by using the IP address or the MAC address of the digital camera.
However, the communication method disclosed in the above-mentioned patent document has a problem in that it is difficult to maintain secrecy. That is, because a code image displayed on a monitor of own digital camera (hereinafter, “own apparatus”) cannot be prevented from being taken by a third digital camera which is different from the other digital camera (hereinafter, other apparatus) to be communicated with the own apparatus, it is possible that the third digital camera receives image data from the own apparatus.
Because the own apparatus allows the other apparatus to take a photo of the code image in order to transfer the code data containing an IP address or a MAC address of the own apparatus, it is considered to send the code data to the other apparatus using, for example, infrared communication. The infrared communication does not require an IP address or a MAC address to initiate communication. Thus, if the own apparatus initially sends the code data to the other apparatus, thereafter, the own apparatus (digital camera A) and the other apparatus (digital camera B) can exchange image data according to a high-speed wireless LAN or the like.
However, in order for the own apparatus and the other apparatus to make infrared communication, it is necessary to mount an infrared communication device to each of the own apparatus and the other apparatus, which increases a manufacturing cost of the own apparatus and the other apparatus. Additionally, it is difficult to make communication if the light emitting and receiving elements of the own apparatus and the other apparatus do not face each other because infrared rays have relatively high directivity. It is not easy for users of the own apparatus and the other apparatus to hold the own apparatus and the other apparatus by hand to cause the light emitting and receiving elements of the own apparatus and the other apparatus to face each other because the light emitting and receiving elements of the own apparatus and the other apparatus are relatively small in size. Thus, it is preferable to place the own apparatus and the other apparatus on a flat surface such as a desk top. In such a case, however, the light emitting and receiving elements of the infrared communication devices of the own apparatus and other apparatus do not always face each other in the state where the own apparatus and the other apparatus are placed on a flat surface.
If the directivity of infrared rays is weakened or infrared rays are strengthened in order to reduce influences of the directivity of infrared rays, there is a risk that a third digital camera, which is different from the other apparatus, can make infrared communication with the own apparatus. Therefore, in consideration of manufacturing cost, convenience of use and maintenance of secrecy, transferring code data according to photographing of a code image is more suitable than transferring code data according to infrared communication.